HDK® pyrogenic silicas are white, amorphous powders of low density and large specific surface area. This high surface-area-to-mass ratio is responsible for the outstanding rheology effect of HDK® products. At the European Coatings Show 2017, WACKER will present four HDK® grades for advanced paint, coating and adhesive applications.

Enhanced Rheology Control

The hydrophobic HDK® H30RM and HDK® H30LM grades feature high specific surface areas and silane modification with pronounced water repellency, which is greater in HDK® H30RM. The two products are particularly suitable for binder systems of high polarity, whereby more pronounced rheology effects can be achieved with HDK® H30RM. Both grades exhibit excellent transparency in clear coats. Furthermore, they are entirely free of polydimethylsiloxane (PDMS) and thus enable crater-free surfaces during coating application. Accordingly, their main applications include surface coatings for the automotive industry and high-quality industrial paints.

Additive with Methacrylic Functionality

HDK® H30RY is a hydrophobic, methacrylic-functional silica. The reactive product can be chemically incorporated into resin networks, enhancing mechanical properties of systems based on vinyl esters, polyesters or acrylates. This yields a broad range of applications – from coatings and adhesives to sealants. Moreover, the properties of dental fillings and nail gels can be optimized with HDK® H30RY.

Excellent Storage Stability in Basic Systems

HDK® H20RH is a hydrophobic silica that has been treated with alkylsilane. The silicone-fluid-free additive features exceptional rheological activity in polar systems and prolongs the shelf life, even at high pH values. It is thus suitable for use in amine hardeners of two-component adhesives. Further application fields include automotive adhesives, half-shell bonding in wind turbines, and chemical anchors. In addition, HDK® H20RH can give jointing compounds favorable pull-off characteristics. It also features good wetting properties. Products formulated with this silica can thus generally be painted over very well after curing.